I. Field of the Invention
The present invention relates to vertical blind assemblies of the type including a horizontally disposed track structure for supporting vertically oriented vanes or blind panels and having an elongate pinion rod rotatably mounted therein. More particularly, the present invention relates to a control unit for controlled rotation of the pinion rod in a vertical blind assembly.
II. Description of the Related Art
Vertical blind assemblies of various types are well known in the art and are available to the consuming public from a number of manufacturers. Most vertical blind assemblies include vertically disposed vanes or panels which are supported from a track structure and capable of being selectively moved along a length of the track structure. Additionally, these assemblies provide for synchronized angular adjustment of the vanes collectively into a common angular orientation about their respective longitudinal axis. In many vertical blind assemblies, the angular adjustment of the vanes is achieved by a pinion rod which engages a gear structure on a carrier assembly attached to each vane. Upon rotation of the pinion rod, each of the vanes are simultaneously turned in synchronized fashion to a common angular orientation. The individual carrier assemblies, each supporting an individual vane, are positionable along the length of the track structure or selectively they may be retracted into a closely bunched adjacent position near one end of the track structure.
The elongate pinion rods used in these type of vertical blind assemblies are manufactured in various sizes and are generally classified in the field based on the number of elongate ridges they have about their outer surface, such as 8 prong or 3 prong. An 8 prong pinion rod would have 8 generally parallel ridges running along its length, forming a groove or trough between adjacent ridges. The ridges and grooves act as gear teeth engaging the associated gear structure attached to the top of each of the individual vanes along the length of the pinion rod.
When the pinion rods are manufactured, there is inevitably a degree of error resulting in a slight twist being introduced to the rod. This twist causes the ridges to spiral very slightly between opposite ends of the pinion rod. The twist in the rod results in the failure of all vanes to fully turn through a complete range of movement between an open position and a closed position, especially with longer track structures having a long pinion rod and a large number of vanes there-along. In an attempt to overcome this problem, many users of vertical blind assemblies apply an increased amount of torque to the pinion rod by pulling harder on the control mechanism pull chain. This causes the pinion rod to first coil and upon release of the pull chain, to recoil or back-off resulting in unwanted reverse turning of the vanes. This is especially noticed when closing the vanes so that their edges overlap with one another. Once fully closed, upon releasing the pull chain a number of the vanes towards one end of the assembly may be caused to move in a reverse direction, resulting in the separation of the overlapping edges and leaving a gap between adjacent vanes.
Another problem associated with the vertical blind assemblies in the related art is the undesireable movement of the vanes caused by externally applied forces, such as wind. Often a strong breeze will cause the vanes to turn if a window or sliding doors adjacent to the vanes are left open. Additionally, if one or more vanes are forced to turn, such as by a person passing through the blinds of a doorway, all of the vanes along the length of the assembly will be turned from their adjusted set position. This has been found to be a nuisance to many people who must constantly re-adjust their vertical blinds whenever there is a strong breeze or when someone passing through the blinds disturbs any of the vanes.
Accordingly, in view of the above-mentioned problems associated with the vertical blind assemblies in the prior art, there is a need for a vertical blind control mechanism which will allow for fine tuned, synchronized adjustment of the vanes and which will further prevent recoiling or unwanted movement of the vanes caused by forces other than that applied by the control mechanism.
It is, therefor, a primary object of the present invention to provide a control unit for use in rotating the pinion rod of a vertical blind assembly and having means to prevent the pinion rod from rotating due to torque or other forces applied externally of the control unit. Specifically, it is a primary object of the present invention to provide a control unit which includes means to prevent unwanted turning of the vanes due to a recoil of the pinion rod or by an externally applied force to any of the vanes or the pinion rod.
It is another object of the present invention to provide a control unit for use with a vertical blind assembly having means to enable fine tuned synchronized adjustment of the associated vanes.
It is yet a further object of the present invention to provide a control unit for rotating the pinion rod in a vertical blind assembly and which includes reduction gear means adapted to provide a decrease speed of rotation of the pinion rod, thereby providing increased control of adjustment of the vanes.
It is still a further object of the present invention to provide a control unit for rotating the pinion rod in a vertical blind assembly which is structured to apply increased torque when turning the pinion rod, thereby providing for ease of operation.
It is still a further object of the present invention to provide a control unit for a vertical blind assembly having a housing specifically structured to fit within the end of a standard track structure and which will accomodate the vertical passage of a pull cord therethrough, eliminating the need to notch or otherwise modify the track structure of the assembly.
These and other objects and advantages of the present invention will be more readily apparent in the description which follows.